Rotary high speed print drum with staggered type columns



A ril 26, 1966 R. E- WILKINS ETAL ROTARY HIGH SPEED PRINT DRUM WITHSTAGGERED TYPE COLUMNS Filed Nov. 24, 1961 Print Storage Driver l Comp.Driver 1 3a 40 Odd- L Even Comp. 32

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5 g 4 46 Print 3 Compl.

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A T TORNE Y electro-mechanical apparatus.

United States Patent 3,247,788 ROTARY HIGH SPEED PRINT DRUM WITHSTAGGERED TYPE CGLUMNS Robert E. Wilkins, Quincy, and Albert Eng,Broolrline,

Mass, assignors to Honeywell Inc, a corporation of Delaware Filed Nov.24, 1961, Ser. No. 154,603 2 Claims. (Cl. 101-93) A general object ofthe present invention is to provide a new and improved apparatus usefulfor printing using More specifically, the present invention is concernedwith high-speed printing apparatus of the type sometimes referred to asline-at-atime printer wherein the printing apparatus has been arrangedso that there may be a considerable reduction in the mechanism requiredfor effecting the desired printing operation without any materialsacrifice in the speed of operation of the printing apparatus.

Present day electronic data processing systems require that there beprinters associated with the output thereof and that these printers becapable of printing large amounts of data at very high speeds inorder toensure that the data processing system is utilized elliciently.Consequently, line-at-a-time printers have been developed wherein it ispossible to print an entire line of print at essentially the same time.In order to effect this type of printing, it has heretofore been thepractice to provide a printing mechanism wherein each character that isto printed in a particular line of print is printed by a separate anddistinct printing device. One form of apparatus used as a print devicemay be a hammer which is electromechanically actuated and which isarranged to move the paper on which the printing is to be made against arotating type wheel which has print characters arranged in spacedrelationship around the periphery of the print wheel.

A representative form of printer of this type is described in an articleby Earl Masterson et al. entitled A Self-Checking High-Speed Printer,"Proceedings of the Eastern Joint Computer Conference, December 19, 1954in special publication T70. The printer referred to in this articleincludes a type wheel having 130 columns wherein each column wasarranged with a set of characters extending in a column around theperiphery of the type wheel. The number of different charactersavailable in each column depends upon the type of printing desired.However, the number of alpha-numeric characters in a set or column maybe 51 to include the standard characters of the alphabet, the numbers 0through 9, and a selected combination of symbols and punctuation marks.In a printer of this type, the print wheel rotates continuously and as aselected character on the print wheel comes into a printing position ahammer is actuated and moves the paper and associated ribbon or carbonagainst the print wheel so that a print impression is made upon thepaper at that particular position. Since there may be 130 characters tobe printed in a particular line of print, it has heretofore beennecessary to provide 130 separate hammers which are adapted to selectthe desired character associated with each particular print position inthe line.

The building of high-speed printers of this type is costly for thereason that the print wheels are expected to operate at relatively highrotational speeds which may be in the order of 1200 revolutions perminute. Thus, in order to eliect the printing of a particular characterfrom this rotating print Wheel, the timing of the driving of the hammertoward the print wheel must be carried out with a high degree ofaccuracy to ensure that the printing of the desired character will takeplace. Since the print wheel stays in continuous motion, a high degreeof acl the print wheel.

3,247,788 Patented Apr. 26, 1966 curacy must be achieved in the drivingelectronics as well as in the associated mechanical equipment. A timingaccuracy in the low millisecond range has been successfully achieved inmany printers currently on the market. However, the achievement ofsuccess in this precise operation has been accomplished at considerableexpense by holding close tolerances on all dimensions. When this typemechanism is multiplied manifold times, the costs become considerableand thereby limit the fields where such printers may be used.

In accordance with the principles of present invention, the number ofhammers required for effecting line-at-atime printing has beenconsiderably reduced by incorporating a new and novel time-sharingarrangement for a hammer driving mechanism wherein each hammer isadapted to span more than one column of characters on Thisarrangement ofthe print hammer permits, in its elemental form, a reduction in at leasthalf the number of print hammers needed.

It is therefore a further object of the present invention to provide anew and improved printing mechanism of the line-at-atime type whereinthe print hammers used for effecting the printing operation are arrangedto span more than one column of characters on an associated print wheel.

In providing a mechanism of the pr-esent type, it is necessary that thecharacters in each column on the print wheel, which are adapted to beassociated with a single hammer, be arranged so that at any particulartime the hammer is moved adjacent to the wheel, only a single charactercan be printed. This requires that the character position of eachcharacter he eifectively placed in a space with respect to thecharacters in the next adjacent column associated with the print hammerto ensure that the hammer moving toward the print wheel will strike onlya single character. This arrangement further requires that there beassociated electrical control circuitry which will ensure that thedesired character will be appropriately related to the desired positionon the paper whereon the printing is to take place.

A still further object of the invention is then to provide a new andimproved line-at-a-time printing apparatus wherein a print hammer isadapted to span more than one print column and wherein the characters ineach print column are displaced relatively to the associatedcharactersin a print column associated with the hammer so as to ensurethat only a single character will be printed as the print hammer isdriven toward the print wheel.

Another object of the invention is to provide in combination with theforegoing objects a print storage means having a gating means associatedwith each column to be printed which is selectively opened in accordancewith the positioning of the print wheel and at least a pair of gatingmeans associated with each hammer.

The foregoing objects and features of novelty which characterize theinvention, as well as other objects of the invention, are pointed outwith particularity in the claims annexed to and forming a part of thepresent specification. For a better understanding of the invention, itsadvantages and specific objects attained with its use, reference shouldbe had to the accompanying drawings and descriptive matter in whichthere is illustrated and described a preferred embodiment of theinvention.

Of the drawings:

FIGURE 1 is a diagrammatic representation of the invention as it relatesto the actual printing operation to be performed; and

FIGURE 2 illustrates diagrammatic logical circuitry which is adapted foruse for controlling the operation of the apparatus in FIGURE 1.

Referring first to FIGURE 1, the numeral 10 identifies a print wheel ofthe type shown in the aforementioned a article. This print wheel isformed with a plurality of columns of characters .arranged in acircumferential path around the periphery of the wheel 10. The number ofcolumns required will be dependent upon the maximum number of charactersthat must be printed in any particular line of print. The print wheel 19is shown with characters in columns 11, 12 and 13. These columns arearranged so that the characters therein are displaced relative to eachother so that each character in one column lies on a line runningparallel to the axis of the wheel and will fall in a space betweencharacters in the next adjacent column. The driving means for the printWheel 19 is not shown but may be assumed to be a constant speed drivingmotor.

The printing operation is effected by way of the characters formed onthe surface of the print Wheel in the columns as indicated. The actualprinting is accomplished by way of a hammer mechanism 14 having a hammermember 16 and a solenoid driving mechanism 13. The driving mechanismincludes a solenoid having an electrical coil associated therewith foreffecting a desired driving force on the hammer 16 to impel it towardthe wheel 10. A spring 19 is provided for biasing the hammer away fromthe wheel. Not shown between the wheel and the hammer 16 will normallybe an appropriate printing ribbon or carbon and a paper on which theimpression is to be made. The hammer 16 is arranged to have a width, atleast on its print wheel face, such that it will span more than onecolumn of characters on the print wheel 10. As illustrated, the hammer16 is shown to have sufiicient span to extend across both the columns of11 and 12.

The energy for driving the solenoid driving mechanism 18 is produced byway of a driver circuit 20, the latter producing a short pulse ofcurrent suthcient to cause the solenoid 18 to move the hammer mechanismtoward the print wheel and to force the associated paper and carbon,ribbon, or any inking means against the print wheel to effect thedesired printing. In order to initiate the operation of driver circuit20, it is necessary that a signal be generated to indicate that theparticular character that is coming next into position on the printwheel 10 is the character to be printed. For initiating a particularprinting operation, a suitable print storage circuit 22 is provided andthis print storage circuit may store signals representing the particularcharacters to be printed. The print storage circuit 22 may be assumedherein to be a circuit capable of storing the data to be printed in asingle line of print. Consequently, a separate storage means is providedfor each character to be printed in the line. For printing one of thecharacters in column 11, it is assumed that the print storage section 25contains a character associated with column 11. Similarly, storage section 26 is provided for storing a character to be printed from thecolumn 12 on the print wheel 10. Each character in print storage isadapted to be read out through an associated control gate, such as thegates 27 and 28. The gate 27 is considered to be the odd gate in that itis adapted to pass to the output thereof the digital data in thecharacter storage section 25 when a printing operation is to take placewtih respect to the odd column, the column 11, at the print wheel 10.The opening of the gate 27 occurs under the control of an odd-evenswitching circuit 29 which is appropriately synchronized with the printwheel. The output of the circuit 29 may be either the signal 0 or E insynchronism with the displacement of the characters in the columnsspanned by the hammer 16. At the time that a particular character is ina printing position on the print wheel 10 in a particular column, aprint code generator 30 is adapted to produce an output code comparableto that of the character coming up so that this output may be comparedwith the data stored in print storage. The comparison circuitry isindicated at 32 and is adapted to produce a single output pulse in theevent that a comparison of the output from print code generator 30 andthe output of the asso- 4 ciated gating mechanism 27 or 28 indicates thenext character coming up on the print wheel should be printed.

It will be noted that the character storage section 26 has its outputcoupled to the gating section 28, the latter which has its outputbuffered to the input of the comparison circuit 32. The controllingsignal of gate 28 will be the even signal E and consequently this signalwill be derived from the odd-even circuit 29 when the next character upis in column 12 on the print wheel 10.

It will be apparent that the print wheel 10 must have associatedtherewith sufficient hammer mechanisms to ensure that all columns thathave characters thereon may be appropriately printed. Thus, if thereshould be columns of print in a particular line, it will be apparentthat when using the principles described above a total of 65 differenthammers must be used in order to effect the printing operation required.Each hammer must have associated therewith circuitry comparable to thatassociated with the hammer mechanism 14. Thus, a pair of odd-even gatingcircuits 35 and 36 are shown connected to the input comparison circuit38, the latter of which feeds a further driver 40. This driver in turnmay be connected to a further hammer mechanism such as illustrated at14.

Considering the operation of the apparatus illustrated in FIGURE 1, itis first assumed that input data has been inserted into the printstorage register 22 in appropriate locations representative of thelocations where each character is to be printed in the next line ofprint. The time that the print storage 22 will be loaded will normallybe during the time that the paper is being advanced from one line to thenext as is well known in the art. As soon as the paper has been advancedand the print storage circuit has been appropriately loaded, theprinting operation can take place. As the printing operation commences,each of the character storage circuits in the print storage circuit 22will read out in the associated gating circuits 27, 28, 35 and 36.

Each of the character storage circuits is assumed, as discussed below,to be a recirculating-type circuit such that in the event a character isnot read successfully out to the comparison circuit, it may bereinserted back into the register for subsequent analysis. In the eventthat the character to be printed from column 12 is the letter B, thecharacter B must be stored in the storage circuit 26 and, when the evensignal E appears on the gate 28, the code for the character B will beread through the gate 28 into the comparison circuit 32 so that therewill be an appropriate comparison made between this code and the printcode generator 30. A comparison signal will appear on the output ofcomparison circuit 32 and thereby activate the driver circuit 20. Thedriver circuit 20 will produce an output current pulse adequate to causethe hammer 16 to be impelled toward the print wheel 10 to thereby movethe paper and the associated ribbon or carbon into a printingrelationship with respect to the character B formed on the column 12. Itwill be noted that when the hammer 16 is adjacent to column 12 thecharacter B will be lying in the space between the B and the Ccharacters in the column 11. Consequently, this arrangement ensures thatthe fact that hammer 16 may span more than one column of print will notproduce an impression in any place other than the particular columnwhich should be active at that particular instant.

If the next character to be printed in column 11 is the character D, theprint wheel will continue to operate, and as soon as the character Dcomes up as indicated by the output from the print code generator, thereading out of the character D in the character storage section 25 byway of the gate 27 will produce a comparison signal in the comparisoncircuit 32 so that a further printing operation can be carried out. Thiswill continue in all print locations for each line until all charactershave been printed.

Referring next to FIGURE 2, there is here illustrated some furtherlogical circuitry that may be associated with the apparatus illustratedin FIGURE I, particularly in those instances where very high-speedprinting is to be effected. Included in the illustrated circuitry ofFIGURE 2 is further detail of the character storage circuitry associatedwith each character storage circuit of the print storage 22. Thecharacter storage circuit 25 will be seen to comprise a-closed-loopshift register having a pair of recirculation gates 42 and 44. Thus,when a character is read out of the print storage circuit 25, theabsence of a comparison signal, as indicated by the presence of a signalCOMP, will cause the gate 42 to open so that there may be arecirculation of the character into the character circuit storage 25,

The gating circuit 44 is associated with a special function requiredonly under limited circumstances when the occurrence of a signal in thecomparison circuitry is calling for an operation of the hammer mechanismprior to the time that the hammer mechanism has completed an immediatelypreceding printing operation. Thus, in a very high-speed printer, shouldthe letter A be required to appear in print at column positions 11 and12, it will be apparent that the hammer mechanism may not be withdrawnfrom printing the first A in column 11 before the signal calling for theprinting of the letter A in column 12 has occurred. Under thesecircumstances it will be necessary for a second revolution of the printwheel to take place in order to pick up the second A in column 12 beforethe paper is advanced and a further line of print data is inserted inthe storage circuit 22. In order to effect this compensating function,the comparison circuit 32 will produce a signal for activating thedriver 20. The comparison signal from the comparison circuit 32 may alsobe used to set a one-shot multivibrator 46 which will apply a signal toa gate 48 by way of delay circuit 50. The output of the comparisoncircuit 32 is also applied to gate 48.

In the event that the one-shot multivibrator 46 has been set by onecomparison signal from the comparison circuit 32 and a further signalappears at the comparison circuit 32 immediately thereafter, the gate 48will be open and a set signal S will be applied to a hold flip-flop 52.This hold flip-flop, when set, will feed a signal back to the gate 44 topermit recirculation of that particular character which could not beprinted due to the factthat the print hammer had not completed itsprevious printing operation.

A further function performed by the hold circuit 52 may be the delayingof the paper advance to ensure that characters for that particular lineof print will all be printed before the paper does advance. Thus, apaper advance control circuit 54 is .adapted to be switched to a resetstate by the presence of a signal when the hold circuit 52 has been set.When all the printing required in a particular line is completed, aprint-complete circuit 56 may be activated to set the paper advancecontrol 54 so that a further line of print may be printed.

It will be apparent from a consideration of the foregoing that there hasbeen provided a new and improved printing apparatus wherein it ispossible to share the use of a print hammer with more than one column ofprint.

It will be apparent that this arrangement may be modified so that theprint hammer spans more than the two columns illustrated, in which eventthere must be a further staggering and spacing of characters associatedwith the particular columns spanned by the hammer mechanism.

While, in accordance with the provisions of the statutes, there has beenillustrated and described the best forms of the invention known, it willbe apparent to those skilled in the art that changes may be made in theapparatus described without departing from the spirit of the inventionas set forth in the appended claims and that, in some cases, certainfeatures of the invention may be used to advantage without acorresponding use of other features.

Having now described the invention, What is claimed as new and novel andfor which it is desired to secure Letters Patent is:

1. A high-speed line-ata-time printer comprising a rotary print wheelhaving formed on the face thereof a plurality of columns of spacedcharacters with each column extending circumferentially around saidprint wheel and with each character in each column being positioned onthe periphery of said Wheel so that it lies on a longitudinal lineparallel to the axis of said wheel which line is located between thecharacters of an adjacent column of characters, a plurality of printhammers adapted to be driven selectively toward said print wheel toforce a medium on which printing is to take place against said wheel,each of said hammers having an effective face width sufiicient to spanat least two adjacent columns of characters, and selecting meansconnected to drive selectively each of said hammers to print from onecolumn or the other of the adjacent columns of characters, saidlast-named means comprising a data storage register responsive to inputsignals representative of a single line of print to store for each suchline the data to be printed from each. column on said wheel while saidwheel rotates through a single revolution, logic means coupled to saidselecting means for determining the completion of printing of said lineof print in accordance with said stored data, means for normallyadvancing said medium following each revolution of said wheel to effectthe printing of a new line of print after each line of print has beencompleted in accordance with said stored data, and means responsive tosaid logic means for holding said advancing means inactive for more thanone revolution of said wheel upon a determination that the printing ofsaid line of print was not completed in said one revolution.

2. The apparatus of claim 1 wherein said logic means comprise gatingmeans having one input coupled to said selecting means, a one-shotmultivibrator coupled to said one input, delay means coupled between theoutput of said multivibrator and another input of said gating means, theoutput of said gating means being coupled to said advancing means andbeing adapted to control the operation of the latter.

References Cited by the Examiner UNITED STATES PATENTS 2,915,967 12/1959Gehring et al. 101-93 2,978,977 4/1961 Eckert et a1. l0l--93 WILLIAM B.PENN, Primary Examiner. R. A. LEIGHEY, LEONARD W. VARNER, Examiners.

1. A HIGH-SPEED LINE-AT-A-TIME PRINTER COMPRISING A ROTARY PRINT WHEELHAVING FORMED ON THE FACE THEREOF A PLURALITY OF COLUMNS OF SPACEDCHARACTERS WITH EACH COLUMN EXTENDING CIRCUMFERENTIALLY AROUND SAIDPRINT WHEEL AND WITH SAID CHARACTER IN EACH COLUMN BEING POSITIONED ONTHE PERIPHERY OF SAID WHEEL SO THAT IT LIES ON A LONGITUDINAL LINEPARALLEL TO THE AXIS OF SAID WHEEL WHICH LINE IS LOCATED BETWEEN THECHARACTERS OF AN ADJACENT COLUMN OF CHARACTERS, A PLURALITY OF PRINTHAMMERS ADAPTED TO THE DRIVEN SELECTIVELY TOWARD SAID PRINT WHEEL TOFORCE AND MEDIUM ON WHICH PRINTING IS TO TAKE PLACE AGAINST SAID WHEEL,EACH OF SAID HAMMERS HAVING AN EFFECTIVE FACE WIDTH SUFFICIENT TO SPANAT LEAST TWO ADJACENT COLUMNS OF CHARACTERS, AND SELECTING MEANSCONNECTED TO DRIVE SELECTIVELY EACH OF SAID HAMMERS TO PRINT FROM ONECOLUMN OR THE OTHER OF THE ADJACENT COLUMNS OF CHARACTERS, SAIDLAST-NAMED MEANS COMPRISING A DATA STORAGE REGISTER RESPONSIVE TO IMPUTSIGNALS REPRESENTATIVE OF A SINGLE LINE OF PRINT TO STORE FOR EACH SUCHLINE THE DATA TO BE PRINTED FROM EACH COLUMN ON SAID WHEEL WHILE SAIDWHEEL ROTATES THROUGH A SINGLE REVOLUTION,